Robotics Stack Exchange
Robotics Stack Exchange

Questions tagged [kinematics]

Kinematics is the branch of mechanics dealing with the motion of points and objects.

Kinematics is the study of mechanics deal with motion of points and objects without regard to the cause of the motion, such as the movement of jointed robotic arm or the movement of pistons and tappets of an engine.

Forward kinematic equations describe the final position of a robotic arm or other system based on the joint parameters.

Inverse kinematic equations describe the joint parameters necessary to move a robotic arm to a particular position.

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One of the best ways to numerically integrate the velocity?

I need to get position $x$ from integrating velocity $v$. One could use 1st order Euler integration as $x_{t+1} = x_t + \delta * v_t.$ However, doing so leads to errors proportional to sampling time $\delta$. Do you know any more accurate solution…
Courier
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How to understand the angular velocity of link i+1?

My question is a basic one about velocity propagation from link to link, that is how to understand the following equation. $ {^i\omega_{i+1}} = {^i\omega_{i}} + {_{i+1}^{\;\;\;i}{R}} \cdot {\dot{\theta}_{i+1}} \cdot {^{i+1}\hat{Z}_{i+1}} $ The…
Wenzhou Li
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Difference between an underactuated system, and a nonholonomic system

What's the difference between an underactuated system, and a nonholonomic system? I have read that "the car is a good example of a nonholonomic vehicle: it has only two controls, but its configuration space has dimension 3.". But I thought that an…
Karnivaurus
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How to make one robot follow the other in parallel formation

This is quite a basic question. I'm practising robot programming with VRep. I have 2 K3 robots in the scene. One robot follows a predefined path. I want the second robot to move "in parallel" with the first one so they keep same orientation and same…
Archer
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Any free or paid software for graphical drawing of Robotics Kinematic Scheme?

I have been searching for days looking for a dedicated software for easily draw kinematic diagrams of robotics like this: I came by this software but it is a bit hard to grasp. Is there any GUI based software instead?
wbadry
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Are operational space and joint space dependent on each other?

Some questions about this, my friends and I argued with this problem. Are operational space and joint space dependent on each other? I know that $x_e$ (end effector's pos.) and $q$ (joint var.) can be expressed by an equation with non-linear…
david
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Confusion over configuration space, workspace and task space

I have been watching Kevin Lynch's videos on Coursera in this series on the basics of robotics. From that I gathered these are the definitions. configuration space is the space of all configurations of the robot. workspace is a specification of…
heretoinfinity
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How to design a differential steering mechanism?

I want to give my robot a differential mechanism for the system of turning and steering. Considering the case of turning a right-angled corner, the robot will achieve this by following a gradual circular arc through the intersection while…
Ghost
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Expressing a global point in different frames

I am trying to express a vector defined in global coordinates in different frames using homogeneous transformation matrices. There are in total 3 frames. Frame 1 lies in the origin and is fixed to the world. Frame 2 is fixed to a floating body,…
jim
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How rotate a point around an arbitrary line in 3D?

I have a body with origin at point A which is represented in homogeneous coordinate of matrix 4x4 and I would like to rotate it around an arbitrary vector in 3D space. I understand how to rotate the body around its own frame axis, but I'm not sure…
nasw_264
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Finding rotation quaternion

I am trying to use a quaternions for robotics and there is one thing I don't understand about it. Most likely because I don't understand how to define position with quaternions and how to define rotation with quaternions if there is any…
arbulgazar
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How many DOFs required to define a 3D pose

I understand that to be able to define point in 3D space, you need three degrees of freedom (DOFs). To additionally define an orientation in 3D space, you need 6 DOFs. This is intuitive to me when each of these DOFs defines the position or…
Karnivaurus
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Inclined Slew Joint Kinematics

I have a robot wrist with a non-typical joint configuration that I have been trying to come up with kinematics equations for. Not sure if there is a common name for it but I have not been able turn anything up during my searches. In short, it…
Justin
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Why is the endeffector of a delta-robot on the slant?

A delta-robot is a nice design for a robot, because it allows to separate the motor from the moving parts. As a result, large and heavy motors with 800 Watt can be used and at the same time the construction remains lightweight and the robot can move…
Manuel Rodriguez
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Kinematic decoupling

Is kinematic decoupling of a 5DOF revolute serial manipulator also valid? The three last joints is a spherical joint. Most literatures only talks about decoupling of 6DOF manipulators. Thanks in advance, Oswald
Oswaldfig
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